Schottky barrier rectifier

Abstract

The present disclosure provides a schottky barrier rectifier, comprising: a communication layer; a drift layer provided on a side of the communication layer and forming a heterojunction structure together with the communication layer; anode metal provided on a side of the drift layer away from the communication layer; and cathode metal provided on a side of the communication layer away from the drift layer. The drift layer is provided with a first area, which extends in a direction of thickness thereof, between a surface of the drift layer away from the communication layer and a surface thereof close to the communication layer, the first are a containing a first metal element and the content of the first metal element in the first area changing in the direction of thickness. The rectifier of the present disclosure uses polarized charges formed by a heterojunction, and thus the breakdown voltage of devices may be improved.

What is claimed is: 
     
       1. A schottky barrier rectifier, comprising:
 a communication layer; 
 a drift layer provided on a side of the communication layer, a heterojunction structure being formed between the drift layer and the communication layer; 
 anode metal provided on a side of the drift layer away from the communication layer; and 
 cathode metal provided on a side of the communication layer away from the drift layer; 
 wherein the drift layer is provided with a first area, which extends in a direction of thickness thereof, between a surface of the drift layer away from the communication layer and a surface thereof close to the communication layer, wherein the first area contains a first metal element and a content of the first metal element in the first area changes in the direction of thickness; and 
 the drift layer has a thickness of 100 nm to 100 μm. 
 
     
     
       2. The schottky barrier rectifier according to  claim 1 , wherein the content of the first metal element in the first area decreases from a side away from the communication layer to a side close to the communication layer. 
     
     
       3. The schottky barrier rectifier according to  claim 1 , wherein the content of the first metal element in the drift layer decreases from a side away from the communication layer to a side close to the communication layer. 
     
     
       4. The schottky barrier rectifier according to  claim 3 , wherein the content of the first metal element in the drift layer decreases in a n-order curve from the side away from the communication layer to the side close to the communication layer, wherein, n is a positive integer. 
     
     
       5. The schottky barrier rectifier according to  claim 4 , wherein the n-order curve is a quadratic curve or a cubic curve. 
     
     
       6. The schottky barrier rectifier according to  claim 1 , wherein a material of the drift layer comprises AlGaN and the first metal element is an Al element; or, a material of the drift layer comprises InGaN and the first metal element is an In element. 
     
     
       7. The schottky barrier rectifier according to  claim 1 , wherein the drift layer is made of AlGaN having a chemical formula of Al x Ga 1-x N, the first metal element is an Al element, and a depth from a side away from the communication layer toward the communication layer is y; and, x and y satisfy the following function: x=−ay n +b, where, a and b are constants greater than zero, n is greater than 1, and x ranges from 0 to 1. 
     
     
       8. The schottky barrier rectifier according to  claim 1 , further comprising a first trench provided on the side of the drift layer away from the communication layer. 
     
     
       9. The schottky barrier rectifier according to  claim 8 , further comprising filling material provided inside the first trench and being the same as the anode metal. 
     
     
       10. The schottky barrier rectifier according to  claim 9 , further comprising an oxide liner layer provided between the trench and the filling material. 
     
     
       11. The schottky barrier rectifier according to  claim 10 , wherein the oxide liner layer is made of silicon oxide. 
     
     
       12. The schottky barrier rectifier according to  claim 8 , further comprising filling material arranged inside the first trench, the filling material being any one or a combination of Ti, Al, Ni, W, Au, Ag, Pt, Pb and TiN. 
     
     
       13. The schottky barrier rectifier according to  claim 1 , wherein the communication layer comprises a substrate, a buffer layer provided on a side of the substrate away from the cathode metal and a channel layer provided on a side of the buffer layer away from the substrate, and the channel layer forms the heterojunction structure together with the drift layer. 
     
     
       14. The schottky barrier rectifier according to  claim 13 , further comprising a second trench running through the drift layer, the channel layer and the buffer layer, wherein a metal wiring layer which electrically connects the communication layer and the substrate is provided inside the second trench. 
     
     
       15. The schottky barrier rectifier according to  claim 14 , further comprising an isolation filling layer provided inside the second trench and covering the metal wiring layer, wherein the drift layer and the metal wiring layer are isolated by the isolation filling layer. 
     
     
       16. The schottky barrier rectifier according to  claim 1 , wherein the communication layer comprises a substrate close to the cathode metal and an epitaxial layer close to the drift layer. 
     
     
       17. The schottky barrier rectifier according to  claim 16 , wherein the epitaxial layer is made of lightly-doped GaN. 
     
     
       18. The schottky barrier rectifier according to  claim 17 , wherein a side of the substrate close to the epitaxial layer is made of N-type doped GaN. 
     
     
       19. The schottky barrier rectifier according to  claim 16 , wherein the drift layer comprises a charge layer close to the epitaxial layer and a capping layer away from the epitaxial layer. 
     
     
       20. The schottky barrier rectifier according to  claim 19 , wherein the charge layer is made of AlGaN, and the capping layer is a single-layer structure or a multi-layer structure consisting of any one or a combination of GaN, AlGaN, InGaN and AlN.